Pickup trucks and other vehicles having a cargo-carrying bed are commonly used to transport loads which are too heavy to be manually hoisted, for example, a user might wish to load a small and light vehicle such as a snowmobile, all terrain vehicles (“A.T.V.”) or riding lawn mowers. Such loads are usually loaded onto the truck by pushing or driving them up a ramp and onto the open bed of the truck. Loading of the truck bed in this manner can result in damage to the vehicles or other objects being loaded and injury to persons loading them. An example is the case of loading a vehicle onto a truck bed, using a ramp. The upper edge of the ramp must typically rest solidly on the rear bumper of the truck while the vehicle is being driven up the ramp. If the upper edge overhangs the bumper somewhat, the ramp will become unstable when the weight of the front wheels of the vehicle being loaded is on the overhang. At this point, the ramp will rock and become unstable and the driver may lose control of the vehicle.
On the other hand, if the upper edge of the ramp overhangs the bumper insufficiently, vibration of the vehicle on the ramp may cause the upper edge to fall off the bumper with resulting damage to the vehicle and Injury to the driver.
Similarly, a heavy load such as a large hay bale is manually loaded onto a truck bed only with great difficulty.
It Is known to provide a hoist to assist in the loading or unloading of a truck, consisting generally of a cargo-carrying platform or container for resting on a truck bed and an arm for moving the platform between its travelling position on the truck bed and a loading position where it rests on the ground directly behind the truck. Thus, a heavy load can be readily pushed or driven onto the platform while the platform Is resting flat on the ground. The load is then secured and the platform hoisted onto the truck bed. An actuator such as a hydraulic ram, linked to an arm, moves a platform between the travel position supported on the truck bed and loading/unloading position resting on the ground. For example, U.S. Pat. No. 4,175,904 to Airaksinen discloses a container and associated hoist mechanism, whereby the container is moved by an arm between a position on a truck bed and resting on the ground directly behind a truck bed, with the hoist arranged for moving the container between the two positions. Similar arrangements are disclosed in U.S. Pat. No. 5,601,393 to Waldschmitt and U.S. Pat. No. 6,152,674 to Ogrodnick.
It is desirable to provide a hoist, including an associated container or platform, suitable for use with a relatively light vehicle such as a light truck or pickup truck, which is also capable of bearing and hoisting a relatively heavy load such as a pair of snowmobiles.